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DOI: 10.1055/s-2000-6266
Synthesis of `Molecular Asterisks' via Sequential Cross-Metathesis, Sonogashira and Cyclotrimerization Reactions
Publication History
Publication Date:
31 December 2000 (online)
A series of suitably functionalized C-linked carbohydrate derivatives 9-13 were prepared in good yields from alkenyl glycosides 1-4 by cross-metathesis reaction using Grubbs' catalyst [Cl2(PCy3)2Ru=CHPh]. The reaction was also applied to 6-O-allyl ether 5 and N-Cbz allylamine 6. C-Linked glycopeptide homologue 15 was prepared in 65% yield by cross-metathesis of perbenzylated β-C-allyl mannopyranoside 1 and allyl glycine derivative 8. Finally, amine-ending C-glycoside 11 was subjected to a sequence of deprotection, amidation with p-iodobenzoic acid (EDC, HOBt, DIPEA, r.t., 12 h), Sonogashira reaction [Pd(PPh3)2Cl2, Et3N, 65 °C, 6 h] and treatment with dicobalt octacarbonyl (60 °C, 6 h) to provide a `molecular asterisk' 21 in 53% yield.
cross-metathesis - carbohydrates - glycopeptides - Sonogashira reaction - cyclotrimerization - ruthenium